from typing import List
class Solution:
  def permute(self, nums: List[int]) -> List[List[int]]:
    if len(nums) <= 1:
      return [nums]

    answer = []
    for i, num in enumerate(nums):
      n = nums[:i] + nums[i+1:]
      for y in self.permute(n):
        answer.append([num] + y)
    return answer